Beneficiation of iron ore fines to improve blast furnace productivity

Abstract

Over the last one hundred years of blast furnace iron-making there has been a significant evolution on the production demands of steel plants. JSPL has commissioned two blast furnaces to enhance the plant capacity to 3.0 MTPA. The greatest improvement in blast furnace productivity possibly comes through using quality raw materials. Reduction in gangue content directly helps in reducing the fuel rate since less amount of gangue is to be heated from room temperature to their melting point within the furnace. Slag volume generated per ton of hot metal is the major contributor in restricting the BF performance. High alumina input through iron ore and sinter causes deterioration in sinter quality, particularly with regard to its strength. Alumina being a refractory oxide has most deleterious effect on slag physical characteristics. Lower slag rate also eases the difficulty in slag drainage and work load in the cast house. Thus, reduction in slag rate is one of the means to achieve higher blast furnace productivity. The beneficiation of iron ore has not only improved the utilization of run-of-mine ore for iron making but also it has made substantial improvement in the techno-economic performance of iron making processes in general and Blast Furnace (BF) in particular. The popular technologies available for beneficiation are washing of iron ore and jigging of ore. Iron ore from our captive mines contains high alumina content of around of 2.3% and has been major obstacles in lowering slag rate. Alumina in iron ore fines affects the process of sintering and quality of sinter. Reduction of sinter alumina through use of beneficiated iron ore has always been a major initiative at JSPL. Jindal Steel & Power Limited (JSPL) has attempted to wash iron ore fines successfully, that has improved the % Fe (T) and alumina content in sinter. Consequently there has been an increase in productivity, decrease in slag volume and consequent reduction in coke rate. This paper presents the strategies adopted for enhancing the blast furnace productivity through iron ore beneficiation and some of the results achieved so far at JSPL, Raigarh.